.Field of the Invention
The invention relates to a wind-propelled apparatus, and more particularly to a wind-propelled skateboard.
2. Description of the Prior Art
Wind-propelled vehicles have been known to man since the Phoenicians first navigated their sail boats in the Mediterranean Ocean. Their sail boats included a hull with a deck, a mast joined to the deck of the hull, a boom coupled to the mast, and a sail attached to the mast and the boom. There have been many improvements over these sailboats, but the basic elements have remained the same.
In 1970 a wind-propelled surfboard or windsurfer was introduced to the water-sporting world. The wind propelled surfboard is the subject of U.S. Pat. No. 3,487,800, entitled Wind-propelled Apparatus, issued to Hoyle Schweitzer and James Drake on Jan. 6, 1970. The wind-propelled apparatus includes a mast which is universally mounted on a craft and which supports a boom and a sail, the position of the mast and sail being controllable by a user on the craft, but being substantially free from pivotal restraint in the absence of such control. The wind-propelled apparatus may also include a pair of curved booms, which are arcuately athwart the mast.
Wind-surfing has proved to be a popular outdoor sport, but it is limited to lakes, large rivers, or the ocean. A wind-propelled skateboard for use on land would also prove to be a popular sport, but such an apparatus would require a body member at least the size of a surfboard. A body member the size of a skateboard would not support the mast, the boom, and the sail of the wind-propelled apparatus. It has, therefore, been impractical to make a skateboard into a windskater or wind-propelled skateboard and retain the ride and control characteristics of a skateboard.
There are also other problems other than size restriction which arise in making the skateboard a wind-propelled apparatus. First, because the skateboard travels on virtually frictionless roller bearing wheels over a solid surface such as a concrete or asphalt, a skateboard tends to maintain its momentum thereby making stopping difficult. When the skateboarder does not wish to gain any more momentum, he must be able to immediately deflate his sail. By contrast the windsurfer has its momentum reduced constantly by the drag created betweenn the surfboard and the water; there is no need to deflate the sail of the windsurfer. Second, when a windskater gets into trouble or when a dangerous obstacle appears before him, he cannot be encumbered by a mast, a boom and a sail mounted on his skateboard, he must, instead, be able to discard them in order to concentrate fully on turning his skateboard away from the obstacles. Again by contrast, the windsurfer has neither a need to discard his mast, boom and sail nor a desire to do so; a windsurfer desiring to slow down may do so by letting go of the boom; the mast, which is universally mounted, the boom and the sail drop into the water remaining attached to the surfboard and the drag of the surfboard and the sail in the water reduces the momentum to a safe level.
According to the Schweitzer patent the difference between a windsurfer and a standard sailboat is that on a sailboat "a sail is provided on a mast that is rigidly secured to the craft in a vertical position . . . . The general effect of providing a sail on a normally sailless vehicle is to convert the vehicle into a water or landboat. Thus by securing a sail to a surfboard, the art of the surfboard and the enjoyment as such is lost and the skill normally required is no longer needed. Instead, one obtains the speed and feel of a light boat and need substantially only those skills appropriate to control a sailboat" (column 1, lines 32-43).
The universal mount of the windsurfer not only provides a wind-propulsion apparatus which preserves the original ride and control characteristics of the surfboard, but also provides an apparatus which is safe in that its sail and its mast be allowed to drop into the water, and which, after the sail and mast has been dropped in the water, may be easily retrieved. It is the presence of the universal mount which distinguishes a windsurfer from a sailboat.
A wind-propelled skateboard in accordance with the Schweitzer patent could not be made because a universal mount will not fit on a skateboard. Furthermore, a skateboarder steers a skateboard by using his feet to change his balance on the skateboard. Any wind-propulsion device must not be too bulky or too unweildy for the skateboarder to steer the skateboard.